Flame inspecting device

ABSTRACT

A transparent ceramic rod for viewing combustion flame carries a ceramic tube at its inner end having higher fire resistance than that of the ceramic rod with the end of the rod recessed therein. The flame is observed from the other end of the rod by the observer.

United States Patent Inventors Sbigeo Kuwayama;

Motohiko Yagi, both of Odawara-shi, Japan Dec. 29, 1969 Aug. 3, 197 1 Fuji Photo Film Co., Ltd. Ashigara-Kamignn, Kanagawa, Japan Appl. No. Filed Patented Assignee FLAME INSPECTING nEvlcE 5 Claims, 3 Drawing F1 Int. CL G0lj 5/48 Field ofSearch 356/43, 50; 73/355 References Cited UNITED STATES PATENTS 3,117,024 1/1964 Ross il8/49 Primary Examiner-Ronald L. Wibert l @5491? r LLMSQEQW Att0rney--Sughrue, Rothwell. Mion, Zinn & Macpeak ABSTRACT: A transparent ceramic rod for viewing combustion flame carries a ceramic tube at its inner end having higher fire resistance than that of the ceramic rod with the end of the rod recessed therein. The flame is observed from the other end of the rod by the observer.

FLAME INSIECTING DEVICE BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a device for inspecting or observing the flame or combustion condition ofa gaseous, liquid or solid fuel.

Nowadays, injury of the harmful waste gas of combustion to health has caused a social problem. It is, therefore, very important to isolate the combustion or waste gas discharging part of a combustion apparatus in order to prevent the waste gas from being diffused directly towards the operator, with the viewpoint of harmfulness of the waste gas as well as heat control. I-leretofore, various means for the outward discharging of the waste gas have been employed. But since those means utilize a waste gas guide passage or waste gas diffusion preventing walls, there is the disadvantage that the operator cannot directly observe the combustion flame from the outside. In such conventional combustion apparatus, an inspecting window is provided in the vicinity of the combustion chamber in order to make it possible for the operator to inspect or observe the combustion flame. In such a case, there is the disadvantage, that the observing direction is limited by the position of the window. Another example of a convention inspecting means employs a transparent rod made of glass, quartz glass, crystallized glass and the like having a cone-shaped end inserted into the combustion flame so that the radiation evolved at the heated cone-shaped end within the flame can be observed at the other end of the rod. With this means for inspecting the flame, there are disadvantages as follows. When the temperature of the combustion flame is too high, the glass rod is likely to be softened and distorted, tarnished, or broken. When the temperature rise is too slow in the inspecting glass, the time before showing the combustion condition becomes too great.

In order to prevent the above disadvantages, the end of the glass rod may be covered with other ceramics having higher heat resistance, but they have the same disadvantages as the ones described above after long use.

In order to eliminate the above disadvantages, it is suggested that the transparent ceramic rod be provided, at an end thereof, with a metallic piece having high heat and oxidation resistance. In such a device, the closer the metallic piece to the transparent ceramic rod, the higher the luminous intensity observed by the inspecting device. But, on the other hand, if the metallic piece is too close to the transparent ceramic rod, the end of the ceramic rod is affected by the combustion flame and will be softened, tarnished or broken.

Therefore, the metallic piece cannot be positioned very close to the ceramic rod. If the transparent ceramic rod is straight, the rod can effectively act as a flame inspecting device even if the metallic piece is rather distant from the ceramic rod. But if the transparent ceramic rod is bent and the light path is bent to transmit the radiation to the observer, the luminous intensity is reduced so much, at the bent portion of the rod, that the ceramic rod will not act effectively as an inspecting device.

SUMMARY OF THE INVENTION This invention provides a flame indicator or flame inspecting device wherein the above-described disadvantages are all eliminated. In accordance with the present invention, there is provided a flame inspecting device which comprises a transparent ceramic rod member made of glass, quartz glass, crystalline glass and the like, and a protecting tube made of ceramics having higher fire resistance than that of the ceramic rod member. The ceramics for the protecting tube may be made of, e.g., white crystallized glass, quartz glass, alumina fire resistant material, zirconia refractories, sillimanite refractories and the like. The protecting tube covers the end of the ceramic rod member. The end of the protecting tube on the flame side is in alignment with or projects outward from the end of the ceramic rod member on the flame side. A small space is provided between the internal surface of the protecting tube and the external surface of the transparent ceramic rod member.

In the inspecting device as described above according to this invention, the transparent ceramic rod member will not be softened, deformed, tarnished or broken even if a metallic piece is mounted to the end of the ceramic rod member with a small space between the metallic piece and the end of the rod member to increase the luminous intensity of the inspecting device. This is because the heat of the flame is absorbed by the protecting tube and the transparent ceramic rod member is not heated relatively, on account of the small space between the protecting tube and the rod member. By using such an inspecting device as described above, sufficient amount of radiation can be transmitted through the ceramic rod member even if the rod is bent.

And in this case, if the protecting tube is red hot by the flame, the red radiation raises the luminous intensity of the inspecting device.

The above description involves the case where the color of the combustion flame is blue. In the case where the color of the combustion flame is red, the radiation from the combustion flame can be directly observed by the inspecting device with only the protecting tube disposed at the end of the transparent ceramic rod member without using the heat resistant and oxidation resistant metallic piece.

An object of the present invention is to provide a flame inspecting device wherein a protecting tube is employed to prevent the transparent tube for transmitting the radiation of the flame from being softened, tarnished or broken.

Other objects and a fuller understanding of the invention will be had by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional, side view of an embodiment of the in- I DESCRIPTION OF THE PREFERRED EMBODIMENTS Now referring to the drawings, the flame inspecting device in accordance with the present invention will be described in detail. Referring to FIG. 1, a burner is shown at l on one side of a partition 2. The partition 2 is such as not to transmit the radiation of the flame therethrough. Then the operator cannot see the condition of the flame directly with his eyes. A ceramic rod 3 transmits the radiation from the flame therethrough. A radiant portion 4 of heat resistant metal is mounted on the end of the transparent ceramic rod 3. The ceramic protecting tube is shown at 5 and has an end slightly displaced outwardly from the end of the transparent ceramic rod 3. By this displacement of the radiation receiving end of the ceramic rod from the end of the protecting tube, the inspecting device can be brought as close as possible to the flame without damaging the end of the transparent ceramic rod. By providing the protecting tube at the end of the ceramic rod 3, the radiation receiving end of the ceramic rod 3 can be brought closely to the flame without raising the temperature of the transparent ceramic rod 3. Therefore, a great amount of radiation can be transmitted through the ceramic rod 3 and the flame can be efficiently observed.

Referring to FIG. 2 illustrating another embodiment of the present invention, the partition 2 is provided horizontally rather than vertically as in the embodiment shown in FIG. 1 and therefore the transparent ceramic rod 3 bent by The radiant portion 4 is formed by a spiral thin metallic wire and is supported by a thicker wire 6 having higher heat resistance. The supporting wire 6 is protected by a ceramic tube 7 of higher fire resistance to prevent the wire 6 from being thermally distorted. The ceramic tube 7 is fixed to the top end of the transparent ceramic rod 3. Just as the embodiment shown in FIG. 1, the protecting tube is provided at the end of the transparent ceramic rod 3.

By forming the inspecting device as described above. visible light can be seen at the end of the ceramic rod 3 with faster response through the bent light path.

Referring to FIG. 3, showing still another embodiment of the invention, the radiant portion as shown in FIGS. 1 and 2 is not provided at the end of the transparent ceramic rod 3. This embodiment of the flame inspecting device is used particularly for a red flame which includes large amount of visible rays therein. As in the other embodiments of FIGS. 1 and 2, a protecting tube 5 is provided at the end of the transparent ceramic rod 3. Thus, the end of the ceramic rod 3 can be brought close to the brightest portion of the flame and the flame can be observed with good efficiency.

The invention has been described in detail referring to the drawing, but the invention is not limited to the abovedescribed embodiments. For instance, a light'guiding tube or rod of glass or plastics can be fixed to the side surface of the transparent ceramic rod in order to transmit the radiation from the fixed tubes. By fixing such tubes on the rod side surface, the radiation may be seen from side of the rod and at the desired position. Moreover, the metal radiant portion may be covered with radiant ceramics in order to increase the visible rays evolved therefrom.

Whatl claim is:

I. A flameinspecting device comprising: a transparent ceramic rod member, and a ceramic tube coaxially provided at the end of said ceramic rod member with a small radial spacing therebetween for protecting said rod member from the heat of the flame to be inspected, said ceramic tube being made of ceramics having higher fire resistance than that of said ceramic rod member, and the end of said rod member being recessed from the end of said ceramic tube.

2. A flame-inspecting device as defined in claim 1 wherein a metallic wire is fixed to the end of said ceramic rod member.

3. A flame-inspecting device as defined in claim 2 wherein said metallic wire consists of a thinner top end portion and a thicker supporting portion.

4. A flame-inspecting device as defined in claim 3 wherein said supporting portion of said metallic wire is protected by a ceramic tube which surrounds the same.

5. A flame-inspecting device as defined in claim 2 wherein the end portion of said metallic wire is spiral shaped. 

1. A flame-inspecting device comprising: a transparent ceramic rod member, and a ceramic tube coaxially provided at the end of said ceramic rod member with a small radial spacing therebetween for protecting said rod member from the heat of the flame to be inspected, said ceramic tube being made of ceramics having higher fire resistance than that of said ceramic rod member, and the end of said rod member being recessed from the end of said ceramic tube.
 2. A flame-inspecting device as defined in claim 1 wherein a metallic wire is fixed to the end of said ceramic rod member.
 3. A flame-inspecting device as defined in claim 2 wherein said metallic wire consists of a thinner top end portion and a thicker supporting portion.
 4. A flame-inspecting device as defined in claim 3 wherein said supporting portion of said metallic wire is protected by a ceramic tube which surrounds the same.
 5. A flame-inspecting device as defined in claim 2 wherein the end portion of said metallic wire is spiral shaped. 